Unlike the practice for other chronic disorders such as diabetes mellitus and hypertension, current routine practice in psychiatric settings does not depend on a systematic measurement based approach but rather on global clinical judgment. This approach results in sub-optimal care and less than ideal outcomes. This project will test implementation of measurement based care (MBC) in an ambulatory care setting with an integrated clinical decision support system (CDSS) and an electronic health record (EHR-CDSS). The proposal focuses on the use of MBC to improve the quality of care for patients with major depressive disorder (MDD). Our EHR- CDSS program facilitates MBC and will improve medication management for patients with this chronic disorder, by using information technology (IT) to ensure that clinicians are monitoring three critical response domains (i.e. symptom severity, side-effect burden, &treatment adherence) using standardized measures. The proposed IT system will also provide decision support during each medication treatment phase as well as help prevent medication errors. This project is a collaboration between the University of Texas Southwestern Medical Center and the Centerstone Community Mental Health Center, Inc. Centerstone is a behavioral health services provider that provides treatment throughout the state of Tennessee. The proposed EHR-CDSS facilitating MBC will be instituted in 24 clinics (17 rural/7 urban) by 50 clinicians (26 psychiatrists and 24 nurse practitioners) that treat approximately 8000 patients with MDD. The first year of the project will be primarily devoted to: 1) customization of the CDSS to take into account the specific needs of Centerstone and 2) integration of CDSS into the Centerstone's EHR. The objective in the second and thirds years of the project will be to test the effectiveness of this new EHR-CDSS to increase the use of MBC principles in medication management by participating clinicians treating patients with MDD. In order to fully evaluate effectiveness of the EHR-CDSS, two research studies are proposed. The first study is a comprehensive, system wide evaluation that will include all clinicians that are using the EHR-CDSS and all of their patients with depression that require a treatment change (either switching medication or dose increase). The second study is an in depth evaluation of the impact of the EHR-CDSS on a limited sample of physicians and their patients and directly assesses the use of MBC using a pre-post test design. Goals &Specific Aims: 1. Integrate a CDSS facilitating MBC with physician needs and the EHR at Centerstone and, 2. Evaluate EHR-CDSS's successful promotion of MBC in medication management. This proposal directly aligns with AHRQ's emphasis on creating and diffusing EHR systems, that are capable of providing effective medication management and decision support in ambulatory settings. It also can be used as a model, to improve the quality care of patients with any chronic disorder. Depression is the most common mental health cause for disability and treatments need to be designed to take into account the chronic nature of the disorder. Despite the development of effective treatments over the last 30 years, evidence from practice settings continues to show inadequate antidepressant medication treatment in terms of dose and duration. The major contribution of this proposal as health services research is that it applies our expertise in algorithm/guideline implementation toward the development of a computerized decision support system integrated with an electronic health record with the goal of disseminating the principles of evidenced based treatment for depression in large systems of care.